This thesis is concerned with the design and development of measuring devices for the
characterisation of acoustic transients with high temporal and spatial resolution. Three
new techniques are demonstrated characterising acoustic transients generated by Nd-YAG laser (1060nm, 30ns, 55mJ) assisted breakdown of water and air.
The first technique demonstrates the use of a high power semiconductor laser in a high
speed multiple exposure imaging system. This system developed is capable of
illuminating an event with up to 10 pulses of light at a maximum repetition rate of 5MHz,
with a timing accuracy of ≈5ns. Each semiconductor laser light pulse has a FWHM
duration of 50ns, peak power of 30W, and a wavelength of 860nm. Images of individual
acoustic transients are displayed on the same CCD camera frame, and it was found that
this is best achieved using a dark field imaging technique such as Schlieren imaging. [Continues.]
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy at Loughborough University.